1. Field of the Invention
The present invention relates to a following distance alarming apparatus for preventing collision of a vehicle equipped with the following distance alarming apparatus (hereinafter, simply referred to as xe2x80x9csubject vehiclexe2x80x9d) against a vehicle running ahead (hereinafter, simply referred to as xe2x80x9cpreceding vehiclexe2x80x9d) based on a measurement of a distance from the subject vehicle to the preceding vehicle or based on an output signal of a sensor working with an apparatus controlling the speed of the subject vehicle, and a displaying apparatus for displaying operating states of the following distance alarming apparatus or a change of the following distance.
2. Description of Related Art
Vehicles such as automobiles move independently from each other on a road. Therefore, there might occur an accident such as bumping of vehicles. On a superhighway, in particular, the frequency of rear-end collisions is higher and a high vehicle speed is liable to invite serious results.
The major cause of collision is a following distance that is too short. Under these circumstances, apparatuses have been conventionally proposed for preventing a collision accident between a subject vehicle and a preceding vehicle by using a following distance measuring device. The applicant of the present invention also proposed following distance informing apparatuses for informing a driver of a change of the following distance in the U.S. patent application Ser. No. 08/998,017, filed on Dec. 24, 1997, for which a patent has been granted as U.S. Pat. No. 6,119,068, and in the U.S. patent application Ser. No. 09/670,517, filed on Sep. 26, 2000.
In a state where a plurality of vehicles are driving safely, each driver repeats a series of operations against every change in the following distance to prevent (rear-end) collision and others. For example, if the following distance from the subject vehicle to the preceding vehicle becomes small, a driver of the subject vehicle would ease up on the accelerator pedal or depress the brake pedal to reduce the speed of the subject vehicle. It is considered that failure or delay in the series of such operations contributes to the (rear-end) collision.
The related art described above advantageously allows a driver to readily cope with a change of following distance by informing the driver of the change. The related art, however, has a problem that, when the following distance changes every moment, it is difficult for the driver to instinctively apprehend the change. In particular, a reliable apparatus has not become widespread to date which can prevent rear-end collision and others by accurately detecting failure or delay of the series of operations by a driver due to inattentive driving or the like.
Based on the foregoing, an object of the present invention is to provide a novel, following distance alarming apparatus which checks, when the subject vehicle approaches the preceding vehicle, a driver""s reaction to the decrease of the following distance, based on a change of output signal value of a sensor that generates a signal in accordance with an operation of an accelerator pedal or the like, and generates a warning sound when there is a possibility of collision to prevent an accident from occurring.
Another object of the present invention is directed to improvement of a conventional following distance alarming apparatus, and is to provide a following distance alarming apparatus which accurately responds to the following distance changing every moment.
Yet another object of the present invention is to provide each of the above-described apparatuses with an optimal displaying apparatus, so as to provide a following distance alarming apparatus which allows operating states of the apparatus to be apprehended at a glance and is improved in practicability and reliability as a guide to safe driving.
The following distance alarming apparatus according to an aspect of the present invention for achieving the above objects is a following distance alarming apparatus that is connected to receive output signals of a following distance measuring device and a sensor having an output signal value that changes in accordance with a driver""s operation for speed adjustment of a subject vehicle. The apparatus includes a memory connectable to receive the output signal value from the sensor and, when the output signal value from the sensor remained unchanged for a prescribed time period, storing a reference value for the output signal value of the sensor based on the output signal value from the sensor, and a first alarming circuit connectable to receive the output signal values from the sensor and the following distance measuring device and further connected to the memory, and determining a possibility of collision of the subject vehicle with a preceding vehicle, based on the following distance measured by the following distance measuring device when the output signal value from the sensor remained unchanged for the prescribed time period, the output signal value from the sensor and the reference value stored in the memory, to output a warning sound.
The following distance alarming apparatus according to another aspect of the present invention is connected to receive output signals of a following distance measuring device and a sensor having an output signal value that changes in accordance with a driver""s operation for speed adjustment of a subject vehicle. The apparatus includes a memory connectable to receive the output signal of the following distance measuring device and, when it is detected that the subject vehicle and a preceding vehicle maintained a follow-up travel state for a prescribed time period based on a following distance measured by the following distance measuring device, storing a reference value determined based on the output signal value from the sensor at that time, a first alarming circuit connectable to receive the output signals of the sensor and the following distance measuring device and further connected to the memory, and, when the following distance measured by the following distance measuring device coincided with an alarm distance determined corresponding to the following distance at the time of the follow-up travel state, determining a possibility of collision of the subject vehicle with a preceding vehicle based on the output signal value from the sensor and the reference value stored in the memory, to output a warning sound, a circuit for, when it is detected that the subject vehicle and a preceding vehicle have maintained a follow-up travel state for a prescribed time period again, causing the memory to store a reference value determined based upon the output value of the sensor, and a second alarming circuit, responsive to the output signal value from the sensor having satisfied a prescribed relation with the reference value and responsive to the following distance measuring device having measured the alarm distance determined corresponding to the following distance at the time of the follow-up travel state, for determining the possibility of collision of the subject vehicle with the preceding vehicle based on the output signal value from the sensor and the reference value stored in the memory, to output the alarm.
The following distance alarming apparatus according to a further aspect of the present invention includes an alarm unit outputting a warning sound, based on a following distance measurement signal, when a following distance between a subject vehicle and a preceding vehicle is reduced to a prescribed value, a detecting unit detecting that an output signal from a sensor having an output signal value changing in accordance with a driver""s operation for control of a speed of the subject vehicle has remained unchanged for a prescribed time period, and a display unit displaying the following distance at which the alarm activates when the detecting unit detected that the output signal of the sensor had remained unchanged for the prescribed time period.
The following distance alarming apparatus according to a still further aspect of the present invention includes an alarm unit outputting a warning sound, based on a following distance measurement signal, when a following distance between a subject vehicle and a preceding vehicle is decreased to a prescribed value, a detecting unit detecting that a value of the following distance measurement signal has remained unchanged for a prescribed time period, and a display unit displaying the following distance at which the alarm unit activates when the detecting unit detected that the value of the following distance measurement signal had remained unchanged for the prescribed time period.
The following distance alarming apparatus according to yet another aspect of the present invention includes an alarm unit outputting a warning sound, based on a following distance measurement signal, when a following distance between a subject vehicle and a preceding vehicle is decreased to a prescribed value, a detecting unit detecting that an output signal from a sensor having an output signal value changing in accordance with a driver""s operation for control of a speed of the subject vehicle has remained unchanged for a prescribed time period, and a display unit displaying a difference between the following distance indicated by the following distance measurement signal and the following distance at which the alarm unit activates when the detecting unit detected that the output signal of the sensor had remained unchanged for the prescribed time period.
The following distance alarming apparatus according to a further aspect of the present invention includes an alarm unit outputting a warning sound, based on a following distance measurement signal, when a following distance between a subject vehicle and a preceding vehicle is decreased to a prescribed value, a detecting unit detecting that a value of the following distance measurement signal has remained unchanged for a prescribed time period, and a display unit displaying a difference between the following distance indicated by the following distance measurement signal and the following distance at which the alarm unit activates when the detecting unit detected that the value of the following distance measurement signal had remained unchanged for the prescribed time period.
The following distance alarming apparatus according to a still further aspect of the present invention includes an alarm unit outputting a warning sound, based on a following distance measurement signal, when a following distance between a subject vehicle and a preceding vehicle is decreased to a prescribed value, an input circuit provided to the subject vehicle, and a display unit displaying a distance at which the alarm unit activates.
The following distance alarming apparatus according to an additional aspect of the present invention includes an alarm unit outputting a warning sound, based on a following distance measurement signal, when a following distance between a subject vehicle and a preceding vehicle is decreased to a prescribed value, an input circuit provided to the subject vehicle, and a display unit displaying a difference between a distance to the preceding vehicle indicated by the following distance measurement signal and a distance at which the alarm unit activates based on an input signal from the input circuit.
The foregoing and other objects, features, aspects and effects of the present invention will become more apparent from the following detailed description of the present invention with reference to the accompanying drawings.